<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<!--
user_pref("layout.css.grid.enabled", true);
-->
<script>
function boom()
{
    document.documentElement.offsetHeight;
    document.getElementById("g").firstChild.remove();
}
</script>
</head>
<body onload="boom();">
<div style="display: grid;" id="g">a b<br></div>
</body>
</html>
